Strength Training for People My Age
I'm pretty sure you know that walking around in the mall -- sometimes more accurately referred to as “shopping” -- is not capable of making anything change for the better. One of the benefits of being a little older is that most of us have had the opportunity to learn that all major improvements come with a price tag. There Ain't No Such Thing As A Free Lunch. Reversing the entropy takes a significant expenditure of energy, and a brisk walk just isn't significant. Sorry.
A daily brisk walk, or a jog, or even a 9-minute pace for three miles can produce enough cardiorespiratory stress to keep your heart and lungs in pretty good shape, true enough. (This of course means that it's not a terribly difficult thing to do.) For most doctors and for many of their patients, the calculation stops there. But not dying of a heart attack is really just a small part of the much larger picture of an active life well-lived. You interact with your environment using all the muscles of your body, not just your heart and diaphragm, and strength is the difference between the things you could do when you were 25 and the things you can't do now.
Strength -- as well as a tolerance for childish nonsense -- is the thing we all lose as we age. Squatting down, standing back up, putting things overhead, pulling things up the driveway, loading the groceries, wrestling with the grandkids, teaching the dog who's boss, mowing the yard, putting the broken lawnmower in the truck again: simple physical tasks we took for granted years ago are often problems for older, weaker people, as well as a source of potential injury that can be expensive and debilitating.
For most of us, this happens because of inactivity. If you do not use your muscles to produce enough force to maintain their ability to do so, it shouldn't be surprising that they become less capable of doing it. And walking, running, riding a bicycle -- physical activities whose performance is not limited by strength for even moderately active people -- cannot increase or even maintain strength.